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Home >> Mazda >> 1997 >> MX-5 Miata Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P1601 - Communication Line Error (Automatic Transmission) >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

  1. Inspect all applicable harness connectors. Repair as needed. Turn ignition on. Access TCM harness connector. TCM is mounted to upper left kick panel, behind instrument panel. Using voltmeter, backprobe applicable TCM harness connector. Measure voltage between terminals No. 2O and 2P.
  2. Battery voltage should be present. If voltage is within specification, go to next step. If voltage is not within specification, repair memory power supply or ground circuit as needed.
  3. Turn ignition off. Disconnect ECM and TCM harness connectors. Using ohmmeter, check continuity between terminal No. 1R on ECM harness connector and terminal No. 1C on TCM harness connector. If continuity exists, go to next step. If continuity does not exist, repair Green wire.
  4. Erase DTC. See CLEARING CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC is present, replace ECM. If DTC is not present, intermittent poor harness connection may have caused DTC to originally set.
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